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1   /*
2    * Licensed to the Apache Software Foundation (ASF) under one
3    * or more contributor license agreements.  See the NOTICE file
4    * distributed with this work for additional information
5    * regarding copyright ownership.  The ASF licenses this file
6    * to you under the Apache License, Version 2.0 (the
7    * "License"); you may not use this file except in compliance
8    * with the License.  You may obtain a copy of the License at
9    *
10   *   http://www.apache.org/licenses/LICENSE-2.0
11   *
12   * Unless required by applicable law or agreed to in writing,
13   * software distributed under the License is distributed on an
14   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
15   * KIND, either express or implied.  See the License for the
16   * specific language governing permissions and limitations
17   * under the License.
18   */
19  package org.apache.myfaces.orchestra.conversation;
20  
21  import java.util.HashMap;
22  import java.util.Map;
23  
24  /**
25   * Maintains a list of aspects the system might attach to a conversation instance.
26   * <p>
27   * Aspects are a way of extending the functionality of a class without modifying it;
28   * it acts something like the "decorator" pattern, but with many different decorator
29   * classes being supported at once.
30   * <p>
31   * In the simplest form, an Aspect can be attached to a Conversation simply as a "marker"
32   * to indicate whether the conversation should be treated in a certain way or not.
33   * <p>
34   * In more sophisticated form, an Aspect can provide an API. Code that wants to
35   * manipulate some "conversation-related" property can query the conversation for the
36   * appropriate Aspect object, then invoke the aspect api to read or write the
37   * Conversation instance via an implementation that is isolated from both the caller
38   * and the Conversation.
39   * <p>
40   * Examples of aspects that can be attached to a conversation are:
41   * <ul>
42   *     <li>Timeout handling</li>
43   *     <li>Access-scope handling</li>
44   * </ul>
45   */
46  public class ConversationAspects
47  {
48      private Map conversationAspects = new HashMap();
49  
50      public void addAspect(ConversationAspect aspect)
51      {
52          conversationAspects.put(aspect.getClass().getName(), aspect);
53      }
54  
55      public ConversationAspect getAspect(Class aspectClass)
56      {
57          return (ConversationAspect) conversationAspects.get(aspectClass.getName());
58      }
59  }